The exponential internet traffic growth projections place enormous transmission rate demand on the underlying information infrastructure at every level. As the response, the 100 Gb/s Ethernet (100 GbE) standard has been adopted recently (IEEE 802.3ba), and 400 GbE and 1 Tb/s Ethernet (1 TbE) are currently under study. Terabit optical Ethernet technologies will be affected by limited bandwidth of information-infrastructure, high energy consumption, and heterogeneity of optical networking infrastructure. To reach beyond 1 Tb/s serial date rates, large signal constellation sizes are required for polarization-division multiplexed (PDM) single-carrier QAM systems, with commercially achievable symbol rates. Furthermore, in the context of high-speed optical communication systems, not only the performance of advanced coded modulation schemes but also their complexity plays a crucial role.
One of the enabling technologies for the next generation of optical transport is the LDPC-coded supperchannel OFDM/multiband OFDM. This approach is typically studied for single mode fiber (SMF) applications, and it is based on conventional QAM scheme. Also, some non-conventional approaches to achieve beyond 1 Tb/s serial optical transport over SMFs include generalized OFDM (GOFDM). Hybrid multidimensional coded modulation (CM), employing both electrical and optical degrees of freedom, can be used to address above constraints in a simultaneous manner. Optical degrees of freedom include the polarization and spatial modes in few-mode fibers (FMFs) and few core fibers (FCF). The electrical degrees of freedom include orthogonal prolate spheroidal wave functions. These degrees of freedom are used as the basis functions for multidimensional signaling.